Multi-membrane balloons are used in balloon catheters. One such use is for angioplasty, for example, in which balloon catheters are introduced into blood vessels, advanced up to a stenosis and dilated at the stenosis site to eliminate the constriction in the blood vessel. A guide wire having a small diameter usually protrudes beyond the balloon catheter at the distal end. The balloon catheter follows the guide wire and conforms to the shape of the respective blood vessel. It is problematic if the balloon bursts due to damage.
It is also known that a multi-membrane balloon may be surrounded by a stiff supporting element (a stent) which may remain in the area of the stenosis as a supporting structure. For example, one or both of the lumens of the membrane sleeves of the double membrane balloon that are arranged one inside the other may be filled with a gas or liquid, for example, and dilated whereupon the stent is dilated to a larger diameter. Such an insertion system for a stent having a multi-membrane balloon is described in U.S. Pat. No. 5,769,817, for example.
International Patent Publication No. WO 2007/053967 describes an insertion system for a stent in which balloon materials having a favorable gliding ability with respect to one another are used. To improve the gliding ability, a lubricant coating may be provided between the membrane layers. The gliding ability of the balloon membranes with respect to one another allows a better adaptability of the multi-membrane balloon to a specific shape of a hollow organ on insertion of the system. Both lumens may be dilated or the membrane balloon may be used as a double-walled design in which only the lumen of the inner balloon is dilated and/or inflated. The membrane layers are then in direct contact with one another and are mutually capable of gliding. For dilatation of the multi-membrane balloons, relatively high pressures are used and are between 50 and 60 bar with the insertion system described hereinbelow.
It is problematic that the stent which is placed around the single-membrane balloon or multi-membrane balloon can easily damage the outer membrane layer if the stent is compressed to a small diameter suitable for insertion of the stent after being pushed onto the balloon. If the balloon, which is not watertight, is dilated at the site of use, then, in the worst case, the stent may be opened only partially and may thus block the artery.